4喷嘴直喷发动机中涡旋对空燃混合过程的影响
The effect on fuel consumption and emissions of switching from two-valve to single-valve EIVC operation inorder to generate swirl intake structures in a four-valve, pent-roof gasoline direct injection (GDI) engine hasbeen investigated. Mie imaging of the fuel spray propagation, along with PIV measurements of the intake flowfield have been taken in an optical engine, and fuel economy and emissions measurements have been made on athermodynamic engine with identical geometry and ancillary systems.The measurements show that fuel economy can be improved substantially when EIVC valve operation is employed,and results differ when only a single inlet valve is activated. Bulk swirl structures are generated in theengine cylinder which affect the atomisation and transportation of the fuel spray and engine performance. Forfuel injection after the inlet valve closing point, the reduction in shear forces and mixing from the intake airstructures is sufficient to cause engine misfires.